The invention relates to a seat, particularly a vehicle seat, of the type having a supporting frame, a spring system fastened at the supporting frame, an upholstered part arranged above the spring system and a spring preload
In the case of a known vehicle seat of this type (DE-OS No. 25 19 901), the borders of the seat cushion cover, for the bracing of the upholstery with the supporting frame or with the spring system, are hung or clamped into a molded-on surrounding U-section at the supporting frame. In order to prevent folds in the seat surface and particularly in the side borders of the cover that are frequently made of other materials, such as imitation leather or the like, the side borders are provided with a certain prestressing and as a result are utilized for providing a certain prestressing to the spring system and a desired contour to the upholstery By means of this tension of the upholstery, a surface hardness is created on the whole seat upholstery which may be desirable in the area of the main body supports, but is found to be uncomfortable in other areas, particularly in the area of the thighs and of the hollows of the knees.
The invention is based on the objective of improving a seat of the initially mentioned type in such a way that it is possible to achieve locally differing hardnesses on the top surface of the upholstery Thus, in certain zones, an increased stiffness is to be created for a better support of the body and in other zones, a soft surface is to be provided for comfortable sitting For example, the edges of the upholstery, during the entering of the motor vehicle, should yield in downward direction (seat cushion) and toward the rear (backrest), but when turns are driven, should provide good lateral guidance without any lateral "swimming".
In the case of a seat of the type mentioned above, this objective is achieved by providing separate fastenin of the cover portion which prestresses the spring system at the supporting frame and of the cover portion at the upholstered part.
By means of the bracing of the cover according to the invention, the upholstery is relieved from pressure by the prestressing of the spring system in the transition area from the upholstery to the spring system. The hardness and the softness of the upholstery can.be selected to differ locally and irrespective of the requirements of the spring system according to work-physiological aspects and sitting comfort.
The development of the seat according to the invention, in this case, may concern the seat cushion as well as the backrest of the seat. In the former case, the supporting frame is connected with a base frame that has guide rails for the fastening in the motor vehicle, or itself forms the supporting frame. In the second case, the supporting frame is fastened at the base frame and projects away from it approximately vertically upwards, in which case the slope of the supporting frame is usually maintained so that it can be adjusted with respect to the base frame.
An advantageous preferred embodiment of the invention includes a weatherstrip or insertion strip connected by sewing to one of the upholstered part and the spring covering part, this strip being also fastened to the other part. A weatherstrip or insertion strip of this type, in addition to being used for the connection of the upper and the lower portion of the cover, while fixing the cover in the additional fastening means located above the supporting frame, is also used for the reinforcement and optical improvement of the connection. By means of the additional fastening of the cover by means of the strip, it is ensured that, on the one hand, the strip is not pulled downward by the prestressing of the spring system that is introduced into the lower portion of the cover after the cover is hung in at the supporting frame with a resultant irregular and unesthetic course of the strip. 0n the other hand, the prestressing in the lower portion of the cover is not imparted to the seat surface area of the cover which leads to the desired soft surface of the upholstery.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.